The present invention relates to the creation of holes in pipes for forming junctions, and more particularly, to the forming of holes in concrete pipes for joining pipe branches in situ.
Building developments require underground piping for various functions, including sewage and storm water run off. These pipe systems are formed by joining pipes within trenches, where the pipes can be readily buried below ground level to provide a smooth ground surface within the development, such as to allow roads to pass over the pipes.
These pipes may typically be formed of concrete sections, and have diameters up to several feet in diameter. Each pipe section is accordingly quite large and heavy. The size and weight of the pipes limits the ability to precisely pre-drill holes in the sides of the pipes to allow branch pipes to be joined. Forming the hole may be easier outside of a trench, however the added requirements for precise placement of the pipe, in the proper orientation to expose the pipe, limit the efficiency with which a pipe system can be installed.
Pipe systems are typically installed by first forming a trench in which the pipe is to lay. Sections of pipe are then placed into the trench, and joined together. A drill or coring machine may then be lowered into the trench, or a branch trench, and fixed to the pipe, such that a hole or core may be formed in the proper location in a sidewall of a pipe. Since the forces associated with creating the core are high, the coring machine must be properly rigged to remain in place while a core is formed. This process is time and labor consuming, and reduces the speed with which a pipe system can be emplaced.
Present coring machines typically use a hydraulic motor to turn a coring bit. The coring bit is similar to a hole saw, however uses a diamond edge to cut the concrete of the pipe being cut. The coring machine typically requires a hydraulic pump to be located near the coring machine to provide high pressure hydraulic fluid for powering the hydraulic motor. The diameter of coring bits are typically in the range of 3″-18″, however the size of the core that may be formed is more limited by the power, and reaction torque, required to turn the coring bit.
Mounting a drill on an articulated arm is known in the art. For example, U.S. Pat. No. 4,099,579 discloses mounting a mast mounted drill rig on an articulated arm. In the '579 patent, a conventional drill is shown mounted through a trunnion to the articulated arm of a back hoe. The mast assembly includes a traverse mechanism for driving the drill into a substance being drilled. The mast mounted system shown, however, is not well adapted to the role of coring pipes, adaptations which the present invention addresses.